Allow sites to disable 'editing' of groups (+- attributes, members and privs) in the UI

Many groups in Grouper will be loaded from authoritative sources. In general these groups should not be edited using the Grouper UI, however, there may be cases where 'empty' groups are created to promote consistency where a group membership may be updated but the group itself not deleted. This can be managed to some extent by appropriate granting (or not) of privileges, however, as GrouperSystem / Wheel group members always have ADMIN a mistake could be made.

I intend to allow a 'hook' in the UI which will allow sites to control whether some aspects of groups can ever be edited in the UI. Currently, at Bristol, I have a group type:

<groupType name="loader_maintained">
<attribute name="attr">y</attribute>
<attribute name="loader">GrouperLoader</attribute>
<attribute name="members-list">n</attribute>
<attribute name="privs">y</attribute>
</groupType>

which I intend to 'test'. I probably need to extend this so that additional group types could be added and related attributes managed in the UI. The hook will not depend on a particular type - rules will be site-implemented, however, a default attribute-based implementation would make sense.